Name: in situ exploration of murine megakaryopoiesis using transmission electron microscopy
Uploaded: 2021-09-08T13:30:00
Description: Watch this Scientific Journal Video about In Situ Exploration of Murine Megakaryopoiesis using Transmission Electron Microscopy at JoVE.com

The authors wish to thank Fabienne Proamer, Jean-Yves Rinckel, David Hoffmann, Monique Freund for technical assistance. This work was supported by ARMESA (Association de Recherche et D&#233;veloppement en M&#233;decine et Sant&#233; Publique), the European Union through the European Regional Development Fund (ERDF) and by Grant ANR-17-CE14-0001-01 to H.d.S.

All animal experiments were performed in accordance with European standards 2010/63/EU and the CREMEAS Committee on the Ethics of Animal Experiments of the University of Strasbourg (Comit&#233; R&#233;gional d&#39;Ethique en Mati&#232;re d&#39;Exp&#233;rimentation Animale Strasbourg). The protocol is schematically shown in Figure 1.
1. Bone marrow collection and fixation (&#160;Figure 1A)
CAUTION: This proced...

<ol>
	<li>Machlus, K. R., Italiano, J. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+incredible+journey:+From+megakaryocyte+development+to+platelet+formation.">The incredible journey: From megakaryocyte development to platelet formation.</a> The Journal of Cell Biology. 201 (6), 785-796 (2013).</li><li>Zucker-Franklin, D., Termin, C. S., Cooper, M. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Structural+changes+in+the+megakaryocytes+of+patients+infected+with+the+human+immune+deficiency+virus+(HIV-1).">Structural changes in the megakaryocytes of patients infected with the human immune deficiency virus (HIV-1).</a> American Journal of Pathology. 134 (6), 9 (1989).</li><li>Eckly, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Biogenesis+of+the+demarcation+membrane+system+(DMS)+in+megakaryocytes.">Biogenesis of the demarcation membrane system (DMS) in megakaryocytes.</a> Blood. 123 (6), 921-930 (2014).</li><li>Scandola, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Use+of+electron+microscopy+to+study+megakaryocytes.">Use of electron microscopy to study megakaryocytes.</a> Platelets. , 1-10 (2020).</li><li>Behnke, O., Forer, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=From+megakaryocytes+to+platelets:+platelet+morphogenesis+takes+place+in+the+bloodstream.">From megakaryocytes to platelets: platelet morphogenesis takes place in the bloodstream.</a> European Journal of Haematology. 60, 3-23 (2009).</li><li>Eckly, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Characterization+of+megakaryocyte+development+in+the+native+bone+marrow+environment.">Characterization of megakaryocyte development in the native bone marrow environment.</a> Platelets and Megakaryocytes. 788, 175-192 (2012).</li><li>Brown, E., Carlin, L. M., Nerlov, C., Lo Celso, C., Poole, A. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Multiple+membrane+extrusion+sites+drive+megakaryocyte+migration+into+bone+marrow+blood+vessels.">Multiple membrane extrusion sites drive megakaryocyte migration into bone marrow blood vessels.</a> Life Science Alliance. 1 (2), 201800061 (2018).</li><li>Eckly, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Megakaryocytes+use+in+vivo+podosome-like+structures+working+collectively+to+penetrate+the+endothelial+barrier+of+bone+marrow+sinusoids.">Megakaryocytes use in vivo podosome-like structures working collectively to penetrate the endothelial barrier of bone marrow sinusoids.</a> Journal of Thrombosis and Haemostasis. , 15024 (2020).</li><li>Cramer, E. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ultrastructure+of+platelet+formation+by+human+megakaryocytes+cultured+with+the+Mpl+ligand.">Ultrastructure of platelet formation by human megakaryocytes cultured with the Mpl ligand.</a> Blood. 89 (7), 2336-2346 (1997).</li><li>Heijnen, H. F. G., Debili, N., Vainchencker, W., Breton-Gorius, J., Geuze, H. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Multivesicular+Bodies+Are+an+Intermediate+Stage+in+the+Formation+of+Platelet+&#945;-Granules.">Multivesicular Bodies Are an Intermediate Stage in the Formation of Platelet &#945;-Granules.</a> Blood. 7 (7), 2313-2325 (1998).</li><li>Gupta, N., Jadhav, K., Shah, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Emperipolesis,+entosis+and+cell+cannibalism:+Demystifying+the+cloud.">Emperipolesis, entosis and cell cannibalism: Demystifying the cloud.</a> Journal of Oral and Maxillofacial Pathology. 21 (1), 92 (2017).</li><li>Centurione, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Increased+and+pathologic+emperipolesis+of+neutrophils+within+megakaryocytes+associated+with+marrow+fibrosis+in+GATA-1low+mice.">Increased and pathologic emperipolesis of neutrophils within megakaryocytes associated with marrow fibrosis in GATA-1low mice.</a> Blood. 104 (12), 3573-3580 (2004).</li><li>Ellis, S. L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+relationship+between+bone,+hemopoietic+stem+cells,+and+vasculature.">The relationship between bone, hemopoietic stem cells, and vasculature.</a> Blood. 118 (6), 1516-1524 (2011).</li><li>Bornert, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cytoskeletal-based+mechanisms+differently+regulate+in+vivo+and+in+vitro+proplatelet+formation.">Cytoskeletal-based mechanisms differently regulate in vivo and in vitro proplatelet formation.</a> Haematologica. , (2020).</li></ol>

Direct examination of megakaryocytes in their native environment is essential to understand megakaryopoiesis and platelet formation. In this manuscript, we provide a transmission electron microscopy method combining bone marrow flushing and fixation by immersion, allowing to dissect in situ the morphology characteristics of the entire process of megakaryocyte morphogenesis taking place in the bone marrow.
The flushing of the bone marrow is a critical step of this method, as the succes...

Megakaryocytes are specialized large polyploid cells, localized in the bone marrow, responsible for platelet production1. They originate from hematopoietic stem cells through an intricate maturation process, during which megakaryocyte precursors progressively increase in size, while undergoing extensive concomitant morphologic changes in the cytoplasm and nucleus2. During maturation, megakaryocytes develop a number of distinguishable structural elements including: a polylobulated nucleus, invaginations of the surface membrane that form the demarcation membrane system (DMS), a peripheral zone devoid of organelles surrounded by the actin based cytoskeletal network, and numerous organelles including &#945;-granules, dense granules, lysosomes, and multiple Golgi complexes. At the ultrastructural level, a major modification observed is the cytoplasmic compartmentalization into discrete regions delimited by the DMS3. This extensive supply of membranes will fuel the extension of long cytoplasmic processes in the initial phase of platelet production, which will then remodel into platelets inside the circulation. Any defect during megakaryocyte differentiation and maturation can affect platelet production in term of platelet count and/or platelet function. 
Thin layer transmission electron microscopy (TEM) has been the imaging approach of choice for decades providing high-quality ultrastructure of megakaryocytes that have shaped our understanding of the physiology of thrombopoiesis4,5. This paper focuses on a standardized TEM method allowing to capture the process of platelet biogenesis occurring in situ within the native bone marrow microenvironment, which could also serve as a basis to analyze any bone marrow cell type. We provide ultrastructural examples of the development of megakaryocytes from immature to fully mature, which extend cytoplasmic processes into the microcirculation of sinusoids6. We also describe an easy procedure to quantify the different megakaryocyte maturation stages, instructing on the regeneration and platelet production capacity of the bone marrow.

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in situ exploration of murine megakaryopoiesis using transmission electron microscopy

Differentiation and maturation of megakaryocytes occur in close association with the cellular and extracellular components of the bone marrow. These processes are characterized by the gradual appearance of essential structures in the megakaryocyte cytoplasm such as a polyploid and polylobulated nucleus, an internal membrane network called demarcation membrane system (DMS) and the dense and alpha granules that will be found in circulating platelets. In this article, we describe a standardized protocol for the in situ ultrastructural study of murine megakaryocytes using transmission electron microscopy (TEM), allowing for the identification of key characteristics defining their maturation stage and cellular density in the bone marrow. Bone marrows are flushed, fixed, dehydrated in ethanol, embedded in plastic resin, and mounted for generating cross-sections. Semi-thin and thin sections are prepared for histological and TEM observations, respectively. This method can be used for any bone marrow cell, in any EM facility and has the advantage of using small sample sizes allowing for the combination of several imaging approaches on the same mouse.

Bone marrow histology 
Observation of the bone marrow toluidine blue histology under a light microscope is key to rapidly analyze the overall tissue architecture in terms of e.g., tissue compactness, microvessel continuity, and the size and shape of megakaryocytes (Figure 1D). It is performed before ultrathin sections to determine the need of cutting deeper in the bone marrow block. Due to their giant size and nuclear lobulation, the more mature megakar...

Watch this Scientific Journal Video about In Situ Exploration of Murine Megakaryopoiesis using Transmission Electron Microscopy at JoVE.com

In Situ Exploration of Murine Megakaryopoiesis using Transmission Electron Microscopy

Here, we present a protocol to analyze ultrastructure of the megakaryocytes in situ using transmission electron microscopy (TEM). Murine bone marrows are collected, fixed, embedded in epoxy resin and cut in ultrathin sections. After contrast staining, the bone marrow is observed under a TEM microscope at 120 kV.

In Situ Exploration of Murine Megakaryopoiesis using Transmission Electron Microscopy

Differentiation and maturation of megakaryocytes occur in close association with the cellular and extracellular components of the bone marrow. These ...

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